The invention relates to insecticide-comprising polymer-based compositions which, in order to recognize the point in time when the insecticide is exhausted, comprise at least one dye which, after the insecticide has evaporated, turns a different colour.
WO 97/29 634 and 99/01 030 disclose insecticidal polymer-based compositions which release the active ingredient at elevated temperature and which can be processed to shaped articles (so-called vapour-producing tablets). The insecticides can be evaporated with the aid of heating devices; the application of the insecticides can thus be controlled as desired.
Dyes which indicate the depletion of the carrier of active ingredient by changing their colour have already been proposed for cellulose-based (cardboard) vapour-producing tablets. This type of dye is unsuitable for polymer-based insecticidal compositions.
One of the requirements which a dye for polymer-based insecticidal compositions must meet is that they must be capable of being distributed homogeneously in the polymer.
A further requirement which such a dye must meet is that no disadvantageous inter-actions with the insecticide result. One of the preferred insecticides of WO 97/29 634 and 99/01 030 is transfluthrin=(2,3,5,6-tetrafluorophenyl)-methyl (1R)-trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate. Thus, the dye to be used in accordance with the invention should be compatible, in particular, with transfluthrin and indicate the exhaustion of the latter by a colour change. Moreover, this colour change should be drastic so that it is easy to notice.
It has now been found that o-cyanoazo dyes which comprise the unit 
are outstandingly suitable for this purpose.
The invention relates to dye-comprising polymer-based insecticidal compositions, characterized in that the dye comprises at least one compound of the formula 
in which
X, Y independently of one another represent CN or NO2 and
R represents an optionally substituted aromatic radical
(with the proviso that Xxe2x95x90Yxe2x95x90NO2 must not apply).
The most important insecticides for the compositions according to the invention are pyrethroids.
The preferred pyrethroid active substances are:
1) 3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d/l-cis/trans-chrysanthemate (allethrin/Pynamin(copyright)),
2) 3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d-cis/trans-chrysanthemate (Pynamin forte(copyright)),
3) 3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d-trans-chrysanthemate (Bioallethrin(copyright)),
4) 2,3,5,6-tetrafluorobenzyl (+)-1R-trans-2,2-dimethyl-3-(2,2-dichlorovinyl)-cyclopropanecarboxylate (transfluthrin, Bayothrin(copyright)),
5) (S)-3-propargyl-2-methyl-cyclopent-2-en-4-on-1-yl (1R)-cis/trans-chrysanthemate (prallethrin/Etoc(copyright)),
or mixtures of these active substances.
Active substances which are particularly preferably used are 3-allyl-2-methyl-cyclopent-2-en-4-on-1-yl d-cis/trans-chrysanthemate (Pynamin forte(copyright)) and
2,3,5,6-tetrafluorobenzyl (+)-1R-trans-2,2-dimethyl-3-(2,2-dichlorovinyl)-cyclopropanecarboxylate(transfluthrin).
The polymer base on which the compositions according to the invention are based comprises at least one polymer with a softening range between 100 and 300xc2x0 C., preferably between 150 and 250xc2x0 C., in particular between 150 and 200xc2x0 C.
In amorphous thermoplastic polymers, the softening range is identified by the glass transition temperature, and in semicrystalline polymers by the melting temperature.
Polymeric materials which are preferably used are amorphous and semicrystalline polymers and mixtures of these which can be processed thermoplastically, that is to say as a viscous melt, and whose softening range is below the boiling point of the active substances to be incorporated under atmospheric pressure. The polymers for the active substance in question are chosen in such a way that the active substance mixes with the polymer at least to some extent.
Suitable polymers which are preferably used are:
PVC (non-rigid), polystyrene, styrenetbutadiene, styrene/acrylonitrile, acrylonitrile/butadiene/styrene, polymethyl acrylate, amorphous polycycloolefins, cellulose esters, aromatic polycarbonates, amorphous aromatic polyamides, polyphenylene ethers, poly(ether) sulphones, polyimides, polyethylene, polypropylene, polybutylene, polymethylpentene, PVC (rigid), polyamide, polyether amides, polyester amides, polyoxymethylene, polyethylene terephthalate, polybutylene terephthalate, polyimide, polyether (ether) ketone and polyurethanes.
Examples of preferred mixtures are:
blends of polycarbonates with polybutylene terephthalate, blends of polyamide-6 and styrene/acrylonitrile, blends of polypropylene and polymethylpentene.
Particularly preferred are polypropylene, poly-4-methyl-1-pentene and mixtures of these.
The compositions according to the invention are preferably based on mixtures comprising
A. 0.1 to 80% by weight, preferably 0.2 to 40% by weight, in particular 0.5 to 20% by weight, specifically 1 to 12% by weight of transfluthrin 
and
B. 99.9 to 20% by weight, preferably 99.8 to 60% by weight, in particular 99.5 to 80% by weight, specifically 99 to 88% by weight of poly-4-methyl-1-pentene which, in turn, can be replaced by another poly-xcex1-olefin to up to half, preferably up to a third, in particular up to a quarter of its weight,
the percentages in each case relating to the total of components A+B.
Transfluthrin and a process for its preparation are disclosed in German Offenlegungsschrift 37 05 224 (=European Patent Specification 279 325).
Poly-4-methyl-1-pentene B is a polymer, preferably with a glass transition temperature of 50 to 60xc2x0 C., a softening temperature measured by the Vicat method (ASTM D 1525) of 140 to 180xc2x0 C., preferably 170 to 175xc2x0 C., and a melt-flow index (260xc2x0 C./5 kg), measured in accordance with ASTM D 1238, of 20 to 200, preferably 22 to 35[g/10 min]; it is known that it can be prepared by polymerizing 4-methyl-1-pentene
Suitable poly-xcex1-olefins which can replace some of the poly-4-methyl-1-pentene are mainly polyethylenes, polypropylenes, polybutenes and polyisobutenes and copolymers of the xcex1-olefins on which the abovementioned polymers are based, such as, for example, ethylene/propylene copolymers. Preferred polypropylenes comprise iso- and/or syndiotactic polypropylenes, preferably with a softening temperature, measured by the Vicat method (ISO 306), of 130 to 170xc2x0 C., preferably 140 to 160xc2x0 C., and a melt-flow index (230xc2x0 C./2 kg), measured in accordance with ISO 1133, of 20 to 40, preferably 25 to 35 [g/10 min].
In the event that xe2x80x9cotherxe2x80x9d poly-xcex1-olefins are concomitantly used, the weight ratio of poly-4-methyl-1-pentene/poly-xcex1-olefins can be 70:30 to 99:1, preferably 80:20 to 95:5.
Radicals R which are suitable for the compounds of the formula (II) are radicals of coupling components of the benzene, naphthalene, indole, pyridine and tetrahydroquinoline series, but preferably N-substituted paminoaryl radicals and, in particular, anilines of the formula 
In this formula,
R1 represents hydrogen, C1-C18-alkyl, C1-C18-alkoxy, C6-C16-aryloxy, C1-C12-alkylcarbonylamino, C6-C12xe2x80x94Arxe2x80x94C1-C4-alkylcarbonylamino, C5-C12-cycloalkylcarbonylamino, C6-C15-arylcarbonyl amino, C1-C5-heteroylcarbonylamino, C1-C12-alkoxycarbonylamino, C1-C12-alkylsulphonylamino, C6-C15-arylsulphonylamino, aminocarbonylamino, CN, CF3, carbamoyl, di-C1-C6-alkylaminocarbonyl, C1-C12-alkoxycarbonyl, sulphamoyl, di-C1-C6-alkylaminosulphonyl or C1-C12-alkylsulphonyl,
R2 represents hydrogen, C1-C18-alkyl, C6-C12xe2x80x94Arxe2x80x94C1-C4-alkyl or C6-C5-aryl,
R3 represents hydrogen, C1-C18-alkyl or C6-C12xe2x80x94Arxe2x80x94C1-C4-alkyl, and
R4 represents hydrogen, C1-C18-alkyl, C1-C18-alkoxy, C5-C15-aryloxy, C6-C12xe2x80x94Arxe2x80x94C1-C4-alkoxy, halogen, CN, carboxyl or C1-C12-alkoxycarbonyl.
The alkyl and alkoxy radicals mentioned above in any desired context (that is to say also, for example, alkylsulphonyl or alkoxycarbonyl) are preferably to be understood as radicals having 1 to 4 C atoms which are preferably monosubstituted by OH, CN, halogen, C1-C4-alkoxy, C2-C5-alkylcarbonyloxy or by ammonium groups of the formula 
where Q1, Q2 and Q3 represent C1-C6-alkyl, C5-C12-cycloalkyl, C6xe2x80x94Arxe2x80x94C1-C4-alkyl or C6-aryl or else form the remaining members of an N-heterocycle such as pyridine, imidazole and triazole, while the aryl or aryloxy radicals are preferably understood as meaning phenyl or phenoxy radicals which are optionally monosubstituted by Cl, Br, NO2, CN, C1-C4-alkoxy or C1-C4-alkyl.
Very particular preference is given to a dye of the formula 
in which
B represents xe2x80x94COxe2x80x94, xe2x80x94CO2xe2x80x94 or xe2x80x94SO2xe2x80x94,
R5 represents C1-C6-alkyl, C6xe2x80x94Arxe2x80x94C1-C4-alkyl, C6-aryl or NV1V2,
V1 represents hydrogen, C1-C18-alkyl, C6xe2x80x94Arxe2x80x94C1-C4-alkyl or C6-C12-aryl,
V2 represents hydrogen, C1-C18-alkyl or C6xe2x80x94Arxe2x80x94C1-C4-alkyl,
R2 represents hydrogen, C1-C18-alkyl, C6xe2x80x94Arxe2x80x94C1-C4-alkyl or C6-C12-aryl,
R3 represents hydrogen, C1-C18-alkyl or C6xe2x80x94Arxe2x80x94C1-C4-alkyl and
R4 represents hydrogen, C1-C18-alkyl, C1-C18-alkoxy, C6-C12-aryloxy or C6xe2x80x94Arxe2x80x94C1-C4-alkoxy
and, preferably, with the proviso that, if R5=NV1V2, then B=xe2x80x94COxe2x80x94 or xe2x80x94SO2xe2x80x94.
Again, the alkyl and alkoxy radicals are preferably understood as meaning those radicals which have 1 to 4 C atoms which are preferably monosubstituted by OH, CN, halogen, C1-C4-alkoxy or C2-C5-alkylcarbonyloxy, while the aryl or aryloxy radicals are preferably understood as meaning phenyl or phenoxy radicals which are optionally monosubstituted by Cl, Br, NO2, CN, C1-C4-alkoxy or C1-C4-alkyl.
It is preferred for the dye for the compositions according to the invention to have the formula 
in which
X represents cyano or nitro,
R2 represents straight-chain or branched C1-C10-alkyl, optionally substituted by halogen, OH, acyloxy, CN or phenyl which, in turn, can be substituted by C1-C4-alkyl or halogen,
R3 represents H and the meanings given for R2 and
R1 represents H, C1-C4-alkyl, C1-C8-acylamino or C1-C4-alkylsulphonylamino.
Preference is given to such a dye of the formula (VII) in which
R1 represents methyl or acetamino.
An especially preferred dye for the compositions according to the invention has one of the following formulae: 
The dyes of the formula (II) and processes for their preparation are known; cf. for example, German Offenlegungsschrift 24 56 495.
Most the dyes to be used in accordance with the invention dye the insecticidal polymer compositions a reddish-blue to blue. The fact that the colour change to colourless is noticed easily is a particular advantage of the invention.
The compositions according to the invention comprise 0.001 to 0.5% by weight, preferably 0.006 to 0.15% by weight, in particular 0.024 to 0.11% by weight of dye (II) based on the total of insecticide and polymer.
The compositions according to the invention generally comprise between 0.1 and 80% by weight, preferably between 0.2 and 40% by weight, particularly preferably between 1.0 and 20% by weight of insecticide, based on the total of insecticide and polymer.
Additives which can be used are modifiers and/or fillers and reinforcing agents and/or processing auxiliaries such as, for example, nucleating agents, plasticizers, release agents, flame retardants, impact resistance modifiers, stabilizers or other additives conventionally used in the thermoplast field. Fillers which are preferably used are those described in the Encyclopedia of Polymer Science and Engineering, Vol. 7, pp. 53-73 (1985).
Fillers and reinforcing agents which can be used are minerals such as, for example, gypsum, lime, glass fibres, sand, titanium(IV) oxide, preferably glass fibres.
The amount of the additives may vary within wide limits; in general, it is 1 to 80% by weight, preferably 0.2 to 50% by weight, in particular 0.5 to 30% by weight, based on additive-comprising composition according to the invention.
The compositions according to the invention can be prepared by introducing the polymer into a suitable kneader or extruder in the form of pellets or a powder, and plastifying it. Insecticide and dye can be directly introduced, under the plastifyng conditions and temperatures which are typical for the polymer, into the polymer melt via a suitable metering device and distributed uniformly therein.
The active-substance-comprising polymers can be pelleted in various ways. For example, either extruded and fully or partly cooled extrudates are cut (extrudate pelletization), or else the hot melt is subjected to die-head pelletization (for example water-cooled die-face pelletization).
The resulting insecticide-comprising granules can be processed thermoplastically to give shaped articles or processed together with other polymers to give blends (master batch).
Shaping methods which can be used are those conventionally used in polymers, such as, for example, injection moulding, extrusion blow-moulding, film extrusion or thermo-forming.
The compositions according to the invention can be used in the form of vapour-releasing tablets in conventional vaporizers as they are employed, for example, for vapour-releasing tablets made of cellulose. Working temperatures from 60 to 180xc2x0 C., preferably 130 to 170xc2x0 C., ensure a relatively uniform long-term release of active substance into the environment.
The invention furthermore relates to the use of the compositions according to the invention for controlling insects such as, for example, flies and midges.